Retrieving the Request Payload values from a HTTPRequest in c#

I am attempting to implement my own LRS for saving TinCanAPI statements and in order to do this I need to retrieve the values sent in the Request Payload which stores the details of the learning activity statement.
When viewing my WebAPI call in developer tools I can see the required values but I have been unable to find them using the Request object.

How Can I retrieve the Request Payload variables from the Request object? I have tried the request object and looked in the Content and Properties fields but I cannot seem to see a Request Payload property to reference in C#. My payload looks as follows: